I don't remember if it's in code guidelines, but everywhere else (at least in code I wrote) it's formatted as
follows (which kinda resembles pattern matching):

```js
let targetWindows = isWindow(target) ? [target] :
                    isActiveTab(target) ? [getOwnerWindow(target)] :
                    isComponentState ? browsers() :
                    isTab(target) ? [] :
                    null;
```